Fused deposition modelling includes extruding material from a nozzle and depositing the material onto a platform in layers or beads. The outlet orifices of most commercially available extrusion nozzles are circular, thus limiting the contact area between the deposited layers and, accordingly, reducing the strength of the final part. In some instances, the nozzles are provided with non-circular orifices. However, such nozzles are oriented relative to the workpiece using passive orientation techniques. For example, nozzle-to-workpiece orientation may be passively provided by a trowel guide that extends from the nozzle and follows the side surface of a previously deposited bead of material. Nozzles including a trowel guide may limit the shapes of the parts produced by fused deposition modelling because the trowel guide may not be able to follow the contours of the workpiece precisely and may dig into the previously deposited material as the nozzle is moved along the workpiece, damaging the workpiece and/or the nozzle.